Safety appliance for steam-boilers.



J. B. KILKENNY. SAFETY APPLIANCE FOR STEAM BOILERS. APPLICATION FILED OCT. 11', 1913.

1,087,496, Patented Feb. 17, 1914.

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UNITED STATES PATENT @FFIGE.

JOSEPH B. KILKENNY, OF WALLA WALLA, WASHINGTON.

SAFETY APPLIANCE FOR STEAM-BOILERS.

Specification of Letters Patent.

Continuation of application Serial No. 745,372, filed Januaryfil, 1913. This application filed October 11,

Serial No. 794,680.

To all whom it may concern Be it known that I, JOSEPH B. KILKENNY, a citizen of the United States, residing at Walla Walla, in the county of \Valla Walla and State of Washington, have invented certain new and useful Improvements in Safety Appliances for SteaniBoilers, of which the following is a specification.

The safety appliance which is the subjectmatter of the present invention is designed for the purpose of instantly relieving the pressure in steam boilers caused by the water getting low and thereby exposing the crown-sheet to the intense heat of the fire, which vaporizes the water so rapidly that the boiler is strained. Ordinarily, a fusible plug is placed in the crown-sheet, which plug, when uncovered by the water getting too low, melts and permits steam and water to flow into the fire-box, thus relieving the pressure and also tending to dampen or extinguish the fire. With such a plug, the crown-sheet is frequently ruined before the water is low enough to expose the plug, resulting often in an explosion with its attendant damage to property and loss of life.

The present invention has for its object to overcome this difiiculty, and to provide,

a safety device which is automatic and highly efficient in operation. This obgect s attained by a novel combination and m rangement of parts to be hereinafter described and claimed.

The present application is a continuation of the application filed January 31, 1913, Serial No. 745372.

In order that the invention may be better understood, reference is had to-the accompanying drawing, in which- Figure 1 is an elevation of a fragment of a steam-boiler, partly broken away, showing the safety device applied thereto. Fig. 2 is an enlarged cross-section of the fusible plug. Fig. 3 is a horizontal section on the line 33 of Fig. 2. Fig. & is an enlarged vertical section of the relief-valve, partly in elevation, and Fig. 5 shows a fragment,

closed in a plug 12 which is externally.

screw-threaded so that it may be screwed into the crown-sheet. The plug 12 has a longitudinal opening 13 extending entirely 7 through the same, into which opening the plug 11 is screwed. That end of the open ing 13 which 15 in the water-space above the crown-sheet is reduced in diameter forming a shoulder 14: which 1s engaged by the inner end of the plug 11. The plug 12 also has a cavity 15 extending laterally from the openmg 13, and'into the top of said plug is screwed a pipe 16 which communicates with' said cavity. The plug 11 has a central longitudinal bore 17 the upper end, or that end which opens into the water-space abovethe crown-sheet, being flared, as indicated at 18, and registering with the reduced end of the opening 13. This bore forms a port, and the same has lateral branches 19 opening through the sides of theplug 11 in the plane of the cavity 15. The plug will be turned so that "certain of the port branches 19 reg ister with'the cavity 15. The port 17 and its branches 19 contain a core 20 of soft fusible metal.

The pipe 16 leads to and opens into one end of a cylinder 21 in which works a piston 22 having'a stem 23 to which is connected a valve 2 1, which latter is located in a casing 25 connected to the steam-dome 26 of the boiler.

The cylinder 21 has two diametrically opposite supports 27 depending from the lower end, which supports terminate at their lower ends in a ring'28 which is screwed into the Valve casing 25, whereby the cylinder is mounted on said valve casing. The outlet fromthe' valve casing'is through the ring 28. The valve 24: seats against the inner end ofthe ring over ports 29 which ports are continued through the support-s27 and also through the wall of thecylinder 21 and open into the latter at that end to which the pipe'16 is connected. The ports 29 there fore form by-passes from the steam-dome to the cylinder. The valve has guide wings 30 working in the ring 28. The pipe 16 and port's 29 are designed to admit steam into the cylinder behind the piston 22. The movement of the piston under the influence of the steam pressure is opposed by a spring 31 infront thereof. The cylinder also has vent ports 32 in front of the piston.

A trap 33 is interposed in the pipe 16 at any convenient point to catch any foreign substances which may be carried through the pipe by the steam.

The operation of the appliance is as follows: If the water gets sufficiently low in the boiler to cause the core 20 to melt, steam and water escape through the port 17 into the fire-box, and thus dampen or extinguish the fire therein. At the same time, steam passes through the branches 19 into the cavity 15 and is carried by the pipe 16 to the cylinder 21 and admitted thereinto behind the piston 22. The area of the piston is greater than that of the valve 24, hence the piston moves downward and the Valve is unseated. Steam from the dome 26 is now also admitted into the cylinder behind the piston, so that the valve is held open until the pressure is reduced, the steam commencing to escape through the ring 28 as soon as the valve is unseated. vVhen the pressure is reduced, the piston is returned by the spring 31, and the valve is again seated.

It will be noted that the plug 11 is entirely incased by theplug 12, which keeps the water back from the former and allows the heat to take action on the soft core 20 sooner than in the ordinary forms of fusible plugs. The core melts before the crownsheet is uncovered and the latter is therefore protected from damage. As the end of the port 17 which opens into the water space is larger than the end which opens into the fire-box, more steam enters the bore than can pass through the smaller end thereof into the fire-box. Thus a portion of the steam under almost, if not the whole boiler pressure, is forced through the port branch 19 into the cavitv 15, and thence to the cylinder 21, as hereinbefore described. Live steam from the dome 26 is admitted behind the piston immediately after the valve opens and holds the same open long enough for the pressure to drop to a safety point.

In the pipe 16, at some convenient point on the outside of the boiler, is a vent 34 for any possible condensation.

The apparatus will operate as well under low steam pressure as under high pressure.

To the pipe 16 is connected apipe 36 which latter makes communication with the steam space of the boiler at 37, and is provided with a valve 38. By this arrangement the ordinary blow of! valve of the boiler may be left off, and the hereinbefore described relief valve substituted therefor. The relief valve will operate as a blow off valve upon opening the valve 38, steam then passing to the cylinder 21, and through the piston 22 opening the valve 24. As a blow off valve is usually required by law, this requirement is complied with by providing the last-described means for operating the relief valve, and the latter may be operated periodically and thus kept in good working condition, which is of vital importance in all. safety appliances. The valve 38 will be kept closed except when the boiler is to be blown off, and it therefore does not afiect the operation of the safety device.

A pipe 41 extends from the pipe 36 to a valve 39 connected to the oil or other liquid fuel supply pipe 40 of the boiler, if the boiler is an oil-burning one. hen the core 20 melts, as hereinbefore described, and the relief valve is operated, steam also passes through the pipes 36 and 41 to the valve 39 and closes the same, thus shutting off the fuel supply to the boiler. F or solid fuel boilers, the parts 41, 39 and 40 will, of course, be left 0E.

Fig. 5 of the drawing shows a slightly modified form of relief-valve, in which the casing has a conduit 42 leading to one of the ports 29. The pipe 16 is connected to the conduit 42. This construction does away with cutting a second hole in the steam dome 26, as the pipe 16 can be connected to the valve casing on the inside.

I claim:

1. A safety appliance for steam boilers comprising a relief valve having its casing connected to the steam space of the boiler, a piston for operating the valve, a cylinder in which the piston operates, a steam supply conduit to the cylinder, and a fusible element mounted in that portion of the boiler wall which isto be protected, said element closing the inlet to the supply conduit, and when fused opening said inlet and also establishing communication between the interior of the boiler and the fire box.

2. A safety appliance for steam boilers comprising a relief valve having its casing connected to the steam space of the boiler, a piston for operating the valve, a cylinder in which the piston operates, a steam supply conduit to the cylinder, a fusible element mounted in that portion of the boiler wall which is to be protected, said element closing the inlet to the supply conduit, and means controlled by the aforesaid valve for admitting additional steam into the cylinder from the steam space of the boiler.

3. A safety appliance for steam boilers comprising a relief valve having its casing connected to the steam space of the boiler, a piston for operating the valve, the area of the piston being greater than that of the valve, a cylinder in which the piston operates, a steam supply conduit to the cylinder,

and a fusible element mounted in that portion of the boiler wall which is to be protected, said element closing the inlet to the supply conduit, and when fused opening said inlet and also establishing communication between the interior of the boiler and the fire box.

4. A safety appliance for steam boilers comprising a relief valve having its casing connected to the steam space of the boiler, a piston for operating the valve, a cylinder in which the piston operates, a steam supply conduit to the cylinder, a plug mounted in that portion of the boiler wall which is to be protected, said plug having a cavity to which the aforesaid conduit is connected, and said cavity also opening into the fire box of the boiler, and a fusible element closing the inlet to the cavity.

5. A safety appliance for steam boilers comprising a relief valve having its casing connected to the steam space of the boiler, a piston for operating the valve, a cylinder in which the piston operates, a steam supply conduit to the cylinder, a plug mounted in that portion of the boiler wall which is to be protected, said plug having a cavity to which the aforesaid conduit is connected, and a longitudinal opening, a plug mounted in the opening and having a longitudinal port and a branch to the aforesaid cavity, and a fusible core in the port and its branch.

6. A safety appliance for steam boilers comprising a relief valve having its casing connected to the steam space of the boiler, a piston for operating the valve, a cylinder in which the piston operates, a steam supply conduit to the cylinder, a plug mounted in that portion of the boiler wall which is to be protected, said plug having a cavity to which the aforesaid conduit is connected, and a longitudinal opening, a plug mounted in the opening and having a longitudinal port and a branch to the aforesaid cavity, the inlet end of the port being larger than its outlet end, and a fusible core in the port and its branch.

7. A safety appliance for steam boilers comprising a relief valve having its casing connected to the steam space of the boiler, a piston for operating the valve, a cylinder in which the piston operates, a steam supply conduit to the cylinder, a plug mounted in that portion of the boiler wall which is to be protected, said plug having a cavity to which the aforesaid conduit is connected, and a longitudinal opening reduced in diameter at one end to form a shoulder, a plug mounted in the opening and having one end abutting against the shoulder, said plug having a longitudinal port and a branch to the aforesaid cavity, the inlet end of the port registering with the reduced end of the aforesaid opening, and a fusible core in the port and its branch.

8. A safety appliance for steam boilers comprising a relief valve casing connected to the steam space of the boiler,-a cylinder having depending supports carrying a ring which is connected to the valve casing, said ring having ports which open through the inner end thereof into the valve casing, from which ports by-passes extend to the cylinder and open thereinto, a piston working in the cylinder, a valve connected to the piston and seating on the ported inner end of the aforesaid ring, a steam supply conduit to the cylinder, and a fusible element mounted in that portion, of the boiler wall which is to be protected, said element closing the inlet to the supply conduit.

9. A safety appliance for steam boilers comprising a relief valve casing connected to the steam space of the boiler, a cylinder having depending supports carrying a ring which is connected to the valve casing, said ring having ports which open through the inner end thereof into the valve casing, from which ports by-passes extend to the cylinder and open thereinto, said bypasses being in the ring, the supports of the cylinder and the wall of the cylinder, a piston working in the cylinder, a valve connected to the piston and seating on the ported inner end of the aforesaid ring, a steam supply conduit to the cylinder, and a fusible element mounted in that portion of the boiler wall which is to be protected, said element closing the inlet to the supply conduit.

10. A safety appliance for steam boilers comprising a relief valve having its casing connected to the steam space of the boiler, a piston for operating the valve, a cylinder in which the piston operates, a steam supply conduit to the cylinder, a fusible element associated with the boiler wall to be protected,

said element closing the inlet to the supply In testimony whereof I atlix my signature in presence of two witnesses.

JOSEPH B. KILKENNY. Witnesses E. E. SAUZE, H. C. BRYSON.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Eatenta, Washington, D. C. 

